at86rf525b ATMEL Corporation, at86rf525b Datasheet - Page 7

• Manufacturer Part Number: at86rf525b
• Description: 2.5ghz Wimax Transceiver
• Manufacturer: ATMEL Corporation

Figure 2. SPI transmission for multiple bytes
5189A–WiMAX–9/07
SDO
SDE
SCL
SDI
X
X
CMD
CMD
SPI Interface
Serial peripheral interface SPI controls the transceiver. This 4-wire bus contains the ports SDE,
SCL, SDI and SDO. The SPI has an 8-bit organization. Each transmission starts with a com-
mand byte with the following structure:
MSB
The command bit CMD is set to “1“ for WRITE operation and “0” for READ operation.
The transmission is continued with the data bytes. The number of data bytes depends on the
register. The MSB of each data byte is send first.
For an 8 bit register:
For 16 bit register:
MSB
MSB
DATA
DATA1
DATA7
CMD
7
5
ADR 6
ADR 6
ADR6
DATA
DATA1
DATA6
ADR 5
ADR 5
6
4
ADR5
DATA
ADR 4
ADR 4
5
DATA1
DATA5
3
ADR4
ADR 3
ADR 3
DATA
4
DATA1
DATA4
2
ADR 2
ADR 2
ADR3
DATA
3
DATA11
DATA3
ADR 1
ADR 1
ADR2
DATA
2
ADR0
ADR 0
DATA1
DATA2
ADR1
DATA
0
1
MSB
MSB
OUT
IN
DATA9
DATA1
ADR0
DATA
LSB
LSB
0
LSB
DATA8
DATA0
OUT
LSB
IN
LSB
7